Family: Umbridae (mudminnows)
Species: Dallia pectoralis (Alaska Blackfish)
This fish grows to 7" in length. It is elongate and cylindrical, with a dark olive-brown coloration. 4-6 dark blotches run vertically along the sides, and the belly is white. The fins have reddish-brown speckles. They are found in swamps, ponds, lakes and streams with vegetation for cover, in tundra and forested locations. Their range is Alaska and the Bering Sea Islands. Alaskan natives used to eat these fish a great deal, having been caught in the fall and frozen for use over the winter.
Family: Cyprinidae (minnows)
Species: Orthodon microlepidotus (Sacramento Blackfish)
This fish grows to 18" in length and is elongate and cylindrical. The back is dark gray, shading to a lighter gray on the sides and below. They are found in the Sacramento-San Joaquin rivers, Clear Lake, a few rivers in California, and in the Truckee River in Nevada. Their habitat is primarily warm fresh waters with very little movement. It is a filter feeder of freshwater plankton, and has a commercial value in that it is sold to oriental fish markets in San Francisco.
Black seabass Centropristis striata is called blackfish in New England and the East Coast
Blackfish is also a name commonly given to pilot whales[?] of the family, Delphinidae.